I don't know of a topic like this exists, so I thought it would be fun to get some ideas across. A lot of us talk about how Goodnites or other smaller diapers are fun, but they are marketed towards children younger than ourselves. This doesn't stop myself or anyone else from still enjoying the products for self-benefit, but it does stop quite a few individuals on this forums, being they aren't small enough to fit.
I have tried Underjams with my 32" waist, and they are small, but still are able to be worn. I have heard the Goodnites run a bit larger, which is hopefully my next diaper purchase. Because these specific diapers are marketed towards the younger folk, they also perform better with the younger folk. Having a smaller sized bottom is sure to help with this.
I don't know how many of you are very knowledgeable in this area, but I did a little research on what you can do to shape your glute "butt" muscles up a bit. It is common knowledge that excercising creates muscle and burns fat according to which region you target such workouts to. Here's the question though, will creating muscle actually decrease the size of your butt? It's not going to decrease the size of your glutes. I've seen women say they are going to excercise these muscles to try and get a bigger butt. It's either common girl knowledge that doing that can in fact give them their desired "big butt" look, or else it is a bogus theory. If anyone could answer this question, I would enjoy reading your responses.
Here is a link for whoever is interested in "shaping" their muscles:
Butt Exercises - Glute Kickbacks